I don't think there's any particular reason for you to jump out of boot services mode if you're just having fun. Runtime mode means the firmware gives up contro

I don't think there's any particular reason for you to jump out of boot services mode if you're just having fun. Runtime mode means the firmware gives up control of devices etc, because you're meant to take over them. As far as the rest of the cores go, I don't think UEFI has much to say about them; you're expected to start them yourself once you've switched to runtime mode, so I expect that means they're just hanging out before then, e.g. during boot services time... you could just start them then.